1. Field
This invention relates to filter presses, specifically presses having a plurality of filter plates adapted for removing or separating solids from liquids. More particularly, this invention is directed to apparatus for separating the filter plates within such a filter press.
2. Statement of the Art
The type of apparatus, known generally as a filter press, is well known in the art. These apparatus are used in various industries to separate solids from liquids. Filter presses may be used to separate solids from suspensions, slurries, and similar aqueous feed streams. Filter presses find application in a variety of industries, e.g. sewage treatment and mining operations.
A filter press generally includes a plurality of separable plates. These plates are slidably held on a frame structure between a fixed support and an opposing moveable support. This moveable support is actuated typically by a hydraulic ram.
The plates are typically arranged in parallel about a horizontal axis. Each plate includes a depression on its side surface. Positioned over that depression is a filter cloth or fabric. Upon the plates being positioned adjacent one another, the opposing depressions in adjacent plates form a cavity wherein the filter cloth is suspended. In order to effect filtering, the plates are compressed one against another by a horizontally mounted hydraulic ram. The compression of the plates, one against another, serves to form a sealed abutment of each plate against its neighboring plates. Thereafter, the fluid or solution, to be processed, may be injected into the plates and through the various cavities defined by the adjacent filter plates. Since the feed stream is fed under pressure into the enclosed cavities, the pressure of the feed stream forces the liquid through the filter cloths. The solids within the stream are embedded on the filter cloths as the liquid passes through the cloths.
When the filtering operation is complete, the hydraulic ram is retracted.
As the filtering plates filter the aqueous feed stream, an increasing quantity of solid material is built up upon the surface of the filter cloths. After reaching a certain quantity, these solid deposits or cakes preclude operation or further use of the filter. In order to continue use of the filter press, the filter plates must be separated one from another and the cakes or solid deposits removed from the filter cloths.
The means and method of separating the filter plates one from another to facilitate the cleaning of the filter cloths is a problem which has confronted the industry for many years. The most rudimentary approach to separating these cloths involves the manual efforts of two or more men using crowbars or other type of wedges to separate one plate from its neighboring plate. Since the plates are forced against one another by a hydraulic ram and further, since various deposits within the filter press itself serve to coalesce and thereby bond one plate to another, the amount of force which must be applied to a filter plate to effect its separation from a neighboring plate may be considerable. Furthermore, the use of human labor in this type of environment involves a considerable amount of safety risk.
As a result, various attempts have been made in the past to devise automated separation systems for use in separating the plates in the filter press after filtration has been effected. Representative of some of these attempts are those which are described in U.S. Pat. No. 4,102,788 (Broad), U.S. Pat. No. 4,359,385 (Krivec), U.S. Pat. No. 3,915,863 (Busse, et al.), U.S. Pat. No. 3,232,435 (Fismer), U.S. Pat. No. 4,272,376 (Schotten), U.S. Pat. No. 4,132,647 (Sakuma) and U.S. Pat. No. 4,105,560 (Fismer).